Image Courtesy of Doobie BrothersFounding Doobie Brothers guitarist Patrick Simmons and his wife, Cris, are planning to go rockin' down the highway together on their vintage motorcycles throughout most of September. The couple will be participating in the Motorcycle Cannonball Endurance Run 2014, a coast-to-coast event that begins September 5 in Daytona Beach, Florida, and will take them on a 4,100-mile journey ending September 21 in Tacoma, Washington.

Cris Simmons will be raising funds for the Stand Up to Cancer charity during the ride in honor of her and Patrick's son, Pat Jr., who was treated for testicular cancer in 2013 and now is free of the disease. Cris, incidentally, is an acclaimed motorcyclist who's a member of the National Motorcycle Hall of Fame, the American Motorcycle Heritage Foundation Motorcycle Hall of Fame, and the Sturgis Motorcycle Hall of Fame.

The Motorcycle Cannonball Endurance Run was first run in 2010 and has been held every other year since. It currently showcases restored motorcycles that were originally built before 1935. Cris previously took part in the 2010 edition of the race, at which she was the only U.S. woman out of the 45 participants.

Patrick Simmons will be riding a 1929 Harley-Davidson JD during this year's race, while his wife will be on a 1934 Harley-Davidson nicknamed "Buddy" after its former owner, famed Hollywood stuntman Bud Ekins. "Pat bought the bike from Bud many years ago and I stole it from Pat in 1993, vowing to ride it 'someday,'" explains Cris.

The Doobie Brothers have had a very busy tour schedule this year, although the band will be taking a break for most of September, allowing Patrick the time to hit the road on his Harley. As previously reported, the group will be releasing a new studio album, Southbound, on November 4 that features duets with a variety of major country stars, as well as contributions from former Doobie Brothers singer/keyboardist Michael McDonald.